I. Field of the Invention
This invention relates to a biaxially oriented laminated film. More particularly, this invention relates to a biaxially oriented laminated film suitable as, for example, the base film of the magnetic recording media, which gives high quality image when used as the base film of the magnetic recording media and which has excellent scratch resistance.
II. Description of the Related Art
A biaxially oriented polyester film containing substantially spherical particles originating from colloidal silica is known and is described in, for example, Japanese Patent Disclosure (Kokai) No. 171623/84. A biaxially oriented laminated film suitable as a base film of magnetic recording media is also known and described in German Patent No. 3414347.5. However, these films have a drawback in that the surface of the film is likely to be scratched with a roll used in, for example, the printing step in the case of films for applications for packaging, or in the step of coating a magnetic solution or in the calendering step in the case of films used as the base film of magnetic recording media. Further, the above-described conventional biaxially oriented films have a drawback in that friction coefficient thereof is increased when the film is handled in an environment with high temperature and high humidity, so that the handling of the film is degraded.
Further, recently, the video tapes which are one of the major applications of the biaxially oriented polyester films are often used for replicating software. That is, video and movie products are copied on the video tapes (packaging medium) from a master tape. With the conventional video tapes, the reduction of the signal/noise ratio (S/N) is large when the dubbing of the video and movie products is carried out at a high speed, so that the image quality of the copied products is degraded. Thus, the dubbing resistance of the conventional video tapes is not satisfactory.